Bimodal N-doped P25-TiO₂/AC composite: Preparation, characterization, physical stability, and synergistic adsorptive-solar photocatalytic removal of sulfamethazine

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• 作者：Pow-Seng Yap^a ; Yan-Ling Cheah^b ; Madhavi Srinivasan^b ; Teik-Thye Lim^a ; ^{cttlim@ntu.edu.sg}
• 关键词：Activated carbon ; Bimodal titania ; Solar photocatalysis ; Sulfamethazine ; Physical stability
• 刊名：Applied Catalysis A ; General
• 出版年：2012
• 期刊代码：4_0926860x
• 类别：ch
• 出版时间：15 June, 2012
• 卷：427-428
• 期：Complete
• 页码：125-136
• 文件大小：1050 K

摘要

A novel nitrogen-doped P25-TiO₂ of bimodal structure with activated carbon supported (N-P25-TiO₂/AC) was synthesized via the modified sol-gel techniques. Besides adding urea as N-source, the N-doping could also be induced through calcination under mixed NH₃/N₂ atmosphere. The composite was characterized using XRD, porosimetry, UV-vis spectrophotometry, FTIR, XPS, SEM/EDX and TEM. The physical stability of the composite was examined through ultrasonication disruption, and the composite exhibited good physical stability. The synergistic effects of the adsorption-solar photocatalysis of sulfamethazine (SMZ) as exhibited by the composites were examined. The best performing bimodal composite was N-P25-TiO₂ (25 + 10)/AC, which comprised 25%of N-P25 and 10%N-TiO₂ (sol) by weight composition (wt%). The maximum adsorption capacity (S_max) for the N-P25-TiO₂ (25 + 10)/AC, at pH 3.0, 6.0 and 10.0 was 183 卤 3, 194 卤 3, and 103 卤 2 mg g^鈭?, respectively. The effects of the total loading of N-doped titania, sol-gel synthesis technique, weight distribution of N-P25 and N-TiO₂ (sol), composite dosage, light wavelength spectrum and solution pH on the photocatalytic degradation (PCD) of SMZ were investigated. The N-P25-TiO₂ (25 + 10)/AC composite exhibited enhanced PCD efficiency under solar irradiation with a pseudo first-order rate constant (k_app) of 0.48 h^鈭?, as compared to other types of bimodal composites because its higher N-P25 content led to a greater photocatalytic activity.